Security Groups With Meta IP

• Query id: adcd0082-e90b-4b63-862b-21899f6e6a48
• Query name: Security Groups With Meta IP
• Platform: CloudFormation
• Severity: High
• Category: Networking and Firewall
• URL: Github

Description

Security Groups allows 0.0.0.0/0 for all ports and protocols.
Documentation

Code samples

Code samples with security vulnerabilities

Postitive test num. 1 - yaml file

Resources:
  Ec2Instance:
    Type: 'AWS::EC2::Instance'
    Properties:
      SecurityGroups:
        - !Ref InstanceSecurityGroup
      KeyName: mykey
      ImageId: ''
  InstanceSecurityGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
        GroupDescription: Allow http to client host
        VpcId:
          Ref: myVPC
        SecurityGroupIngress:
        - IpProtocol: tcp
          FromPort: 0
          ToPort: 65535
          CidrIp: 0.0.0.0/0
        SecurityGroupEgress:
        - IpProtocol: tcp
          FromPort: 80
          ToPort: 80
          CidrIp: 0.0.0.0/0

Postitive test num. 2 - json file

{
  "Resources": {
    "Ec2Instance": {
      "Properties": {
        "SecurityGroups": [
          "InstanceSecurityGroup"
        ],
        "KeyName": "mykey",
        "ImageId": ""
      },
      "Type": "AWS::EC2::Instance"
    },
    "InstanceSecurityGroup": {
      "Type": "AWS::EC2::SecurityGroup",
      "Properties": {
        "GroupDescription": "Allow http to client host",
        "VpcId": {
          "Ref": "myVPC"
        },
        "SecurityGroupIngress": [
          {
            "FromPort": 0,
            "ToPort": 65535,
            "CidrIp": "0.0.0.0/0",
            "IpProtocol": "tcp"
          }
        ],
        "SecurityGroupEgress": [
          {
            "IpProtocol": "tcp",
            "FromPort": 80,
            "ToPort": 80,
            "CidrIp": "0.0.0.0/0"
          }
        ]
      }
    }
  }
}

Code samples without security vulnerabilities

Negative test num. 1 - yaml file

Resources:
  Ec2Instance:
    Type: 'AWS::EC2::Instance'
    Properties:
      SecurityGroups:
        - !Ref InstanceSecurityGroup
      KeyName: mykey
      ImageId: ''
  InstanceSecurityGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
        GroupDescription: Allow http to client host
        VpcId:
          Ref: myVPC
        SecurityGroupIngress:
        - IpProtocol: tcp
          FromPort: 80
          ToPort: 80
          CidrIp: 127.0.0.1/32
        SecurityGroupEgress:
        - IpProtocol: tcp
          FromPort: 80
          ToPort: 80
          CidrIp: 127.0.0.1/33

Negative test num. 2 - json file

{
  "Resources": {
    "Ec2Instance": {
      "Properties": {
        "SecurityGroups": [
          "InstanceSecurityGroup"
        ],
        "KeyName": "mykey",
        "ImageId": ""
      },
      "Type": "AWS::EC2::Instance"
    },
    "InstanceSecurityGroup": {
      "Type": "AWS::EC2::SecurityGroup",
      "Properties": {
        "GroupDescription": "Allow http to client host",
        "VpcId": {
          "Ref": "myVPC"
        },
        "SecurityGroupIngress": [
          {
            "ToPort": 80,
            "CidrIp": "127.0.0.1/32",
            "IpProtocol": "tcp",
            "FromPort": 80
          }
        ],
        "SecurityGroupEgress": [
          {
            "IpProtocol": "tcp",
            "FromPort": 80,
            "ToPort": 80,
            "CidrIp": "127.0.0.1/33"
          }
        ]
      }
    }
  }
}